You can trust his advice based on his past record e.g. wasn't he the one who told Zuckerberg to abandon his music sharing ambitions and focus on Facebook? Or yo

You can trust his advice based on his past record e.g. wasn't he the one who told Zuckerberg to abandon his music sharing ambitions and focus on Facebook? Or you could not trust his advice based on his record, e.g. his credulous investments based on "peak oil". Whether or not he wrote a blog post with some whacko (possibly thought experiment?) idea in it has no bearing on the quality of his advice